1. Field of the Invention
The invention relates generally to power supplies and more particularly to a power supply employing a pulse-generating circuit magnetically coupled to a power supply to provide operating voltage for a remote power switch.
2. Description of the Related Art
Electrically actuated “remote” switches are used to replace mechanical switches in a wide variety of applications. In a recent trend, remote switches are being employed to replace conventional mechanically actuated switches for computer and communications equipment as well as ordinary wall switches in the home. A remote power switch permits service personnel to remotely power down and re-boot computers, servers and the like to remove possible causes of malfunction. Remotely actuated wall switches permit automated control over lighting and home appliances. Further, remotely actuated wall switches allow the user to adjust appliances using a remote control.
Remote power switches require a source of electrical energy to operate. Some remote power switches employ batteries and may include a charging device to maintain a power source for the switch. Batteries tend to be expensive, bulky, environmentally unfriendly and maintenance intensive. Other prior art remote power switches use simple rectifying circuits to tap facility power to provide the necessary operating voltage. Simple, passive circuits connected to facility power suffer from several disadvantages. First, they tend to be inefficient, employing resistance and/or other inactive components that are constantly dissipating facility power and radiate heat into the enclosure occupying the remote power switch. In addition, simple continuously connected power supply circuits do not isolate the control device from facility power. Surges or spikes in facility power may damage the control device. The control device may include a microcontroller or other integrated circuit operating at a radio frequency (RF) and may feed back an interfering signal to the facility power through such simple power supply circuits.